Method of manufacturing nickel electrode for nickel-zinc battery

ABSTRACT

A method of manufacturing nickel electrode for a nickel-zinc battery includes the steps of: providing a nickel oxyhydroxide (NiOOH) and a nickel metal; adding a first additive consisting of transition metal oxide to the nickel oxyhydroxide and the nickel metal; and adding a binder for combining the first additive to the nickel oxyhydroxide and the nickel metal, wherein the first additive contains one or more transition metal oxides selected from a group consisting of ruthenium oxide (RuO 2 ) and rhodium oxide (RhO 2 ). Metal oxide or hydroxide with a rare earth oxide improves the electrode capacity and shelf life. Zinc oxide is added to the cathode to facilitate charger transfer and improve the characteristics of high rate discharging. The cathode significantly increases the charging efficiency, promotes the overpotential of oxygen evolution, and intensifies the depth of discharging, thereby increasing the overall efficiency and lifespan of the battery.

CROSS REFERENCE OF RELATED APPLICATION

This is a Divisional application that claims the benefit of priorityunder 35 U.S.C. §119 to a non-provisional application, application Ser.No. 12/930,221, filed Dec. 31, 2010.

BACKGROUND OF THE PRESENT INVENTION

1. Field of Invention

The present invention relates to a nickel-zinc battery, and moreparticularly to an additive for nickel-zinc battery to increase theefficiency and lifespan of the battery.

2. Description of Related Arts

At present, the growing environmental situation forced many countries toissue strict environmental regulations, green and low-carbon economy hasbecome a trend. As the oil price remains high, the prosperity of interneand electronic products have given rise to new growing markets ofrechargeable batteries. Particularly, the fast growth of hybrid electricvehicle (HEV), plug-in hybrid electric vehicle (PHEV), and electricvehicle (EV) market have led to urgent need of a kind of battery that isof higher energy, higher power, more stable, safer, and moreenvironmental friendly. Conventional battery technologies, such as leadacid and nickel-cadmium batteries, cannot meet the market needs. Inaddition, these batteries are not in line with the requirements ofenvironmental protection. Lithium batteries, though very successful inthe portable electronic applications, cannot meet the requirements oflarge systems due to inadequate power, high price, and risk of safety.

The emerging nickel-zinc (Ni—Zn) battery technology has the potential tofulfill various application needs. The nickel-zinc is a rechargeablebattery with high power and adequate energy while pollution level, risklevel and cost are low since heavy metals such as Pb, Cd, and Hg are notused in the manufacture and the battery is non-flammable.

Despite their advantages, Ni—Zn batteries have unresolved problem ofshort cycle life for many years. The reason of its short cycle life isbelieved to be caused by: (1) zinc dendrites growth during chargingprocess which causes short circuit in the battery and limits its servicelife; (2) zinc which is soluble in alkaline electrolyte and does notkeep in the same place during charging and discharging processes forcausing shape change; and (3) electrode material falling during cyclingleading to loss in cell capacity.

Most of the researches on the Ni—Zn batteries are focused on theprevention of dendrites and/or distortion of Zn anodes, but fewerresearches are aimed at the cathodes. The importance of the cathodecomposition is much neglected. As a common method, the Ni cathode of aNi-MH or Ni—Cd battery is completely employed in the Ni—Zn batteries,leading to poor performance.

The charging efficiency of nickel cathode electrode is low in anickel-zinc battery, especially at the late charging stage. Severalproblems can be caused by the cathode when it is at the low chargingefficiency stage. First, the zinc anode could be overcharged anddendrites are easily built. Second, unwanted and extra oxygen evolutionmay occur at the cathode during charging. Third, the cathode may expandand get loosely packed when overcharged. Fourth, the zinc anode has tobe over-weighted to counter balance the low charging efficiency of thecathode.

In the conventional arts, cobalt and cobalt oxides or hydroxides havebeen applied in the cathode for increasing the charging efficiency,promoting the overpotential of oxygen evolution, and intensifying thedepth of discharging. In theory, the metal cobalt cannot be dissolved inalkali. However, the cobalt in the surface is unavoidably oxidized.Then, the cobalt oxides and its hydroxides can both be dissolved in thealkali liquid, imposing safety concern to the battery.

When cobalt compounds dissolved within the alkali electrolyte, it willcontact with the Zn electrode. Then the cobalt compounds will promotehydrogen evolution at the Zn electrode, resulting in great riskconcerning safety and making the battery fail to meet the requirementsof application. Therefore, it is apparent that the cobalt additive isnot a solution for a Ni—Zn battery to increase the charging efficiency,promote the overpotential of oxygen evolution, intensify the depth ofdischarging, while maintaining the high power capability andenvironmental friendliness of the nickel-zinc battery.

SUMMARY OF THE PRESENT INVENTION

The invention is advantageous in that its put the much neglecteddevelopment area of a Ni—Zn battery into the center place ofdevelopment. Instead of handling the dendrite and deformation problemsof the Ni—Zn battery, the present invention puts the focus on theelectrode. In fact, the performance of a cathode is the key to theentire battery, which should be the most influential factor for theoverall efficiency of a battery.

Another advantage of the invention is to provide an additive for nickelcathode that can increase the charging efficiency, promote theoverpotential of oxygen evolution, and intensify the depth ofdischarging, while still maintaining the high power capability andenvironmental friendliness of the nickel-zinc battery.

Another advantage of the invention is to provide an additive fornickel-zinc battery to increase the efficiency and lifespan of thebattery.

Another advantage of the invention is to provide a kind of cathodeadditive for nickel-zinc battery to increase the efficiency and lifespanof the battery.

Another advantage of the invention is to provide a nickel cathode fornickel-zinc battery which is long life, capable of long-term storage andhaving excellent performance of high rate discharging, thereby capableof increasing the overall efficiency and lifespan of the nickel-zincbattery.

Another advantage of the invention is to provide a nickel cathode fornickel-zinc battery which is capable of having an increased chargingefficiency, promoting over-potential of oxygen evolution at the cathode,intensify a depth of discharging property and increasing capacity of thecathode, such that the cycle life, shelf life and storage life of thecell employing the nickel cathode of the present invention are improved.

Another advantage of the invention is to provide an improved nickelcathode for nickel-zinc battery which is long life, capable of long-termstorage and having excellent performance of high rate discharging, whileproviding a simple structure, low cost manufacture and improved safety,thereby capable of increasing the overall efficiency and lifespan of thenickel-zinc battery.

Additional advantages and features of the invention will become apparentfrom the description which follows, and may be realized by means of theinstrumentalities and combinations particular point out in the appendedclaims.

According to the present invention, the foregoing and other objects andadvantages are attained by a composition for electrode of a nickel-zincbattery, consisting of:

a nickel oxyhydroxide having a concentration from approximately 50% to98% by weight;

a nickel metal powder having a concentration from approximately 1% to20% by weight;

a first additive of a transition metal oxide having a concentration fromapproximately 0.05% to 5% by weight, wherein the first additive isruthenium oxide (RuO2), rhodium oxide (Rh02) and/or their combination;

a second additive of oxide mixture having a concentration fromapproximately 0.05% to 5% by weight; and

a binder having a concentration from approximately 0.05% to 5% by weightof solid content.

In accordance with another aspect of the invention, the presentinvention comprises a method of manufacture of nickel electrode for anickel-zinc battery, comprising the steps of:

(a) providing a nickel oxyhydroxide (NiOOH) and a nickel metal;

(b.1) adding a first additive consisting of transition metal oxidecontaining ruthenium oxide (RuO2) and/or rhodium oxide (Rh02) to thenickel oxyhydroxide and the nickel metal;

(b.2) adding a second additive consisting of metal oxide or hydroxidewith one or more rare earth oxide to the nickel oxyhydroxide and thenickel metal to increase an electrode capacity and a shelf life of thenickel electrode; and

(c) adding a binder for combining the first and second additive to thenickel oxyhydroxide and the nickel metal,

wherein the nickel oxyhydroxide has a concentration from approximately50% to 98% by weight, the nickel metal powder has a concentration fromapproximately 1% to 20% by weight, the first additive has aconcentration from approximately 0.05% to 5% by weight, the secondadditive has a concentration from approximately 0.05% to 5% by weightand the binder has a concentration from approximately 0.05% to 5% byweight of solid content.

Optionally, zinc oxide (ZnO) or hydroxide (Zn(OH)2), having aconcentration from approximately 0.1% to 5% by weight can be added tofacilitate charger transfer and increase high-rate discharging ability.

Still further objects and advantages will become apparent from aconsideration of the ensuing description and drawings.

These and other objectives, features, and advantages of the presentinvention will become apparent from the following detailed description,the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a Nickel-Zinc battery according to apreferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

According to the preferred embodiment of the present invention, a cellconstruct for a nickel-zinc battery includes an additive to increase theefficiency and lifespan of the battery is provided. Preferably, theadditive for nickel-zinc battery is a kind of cathode additive forproviding features of long life, long-term storage and excellentperformance of high rate discharging, to the cathode, thereby increasingthe overall efficiency and lifespan of the nickel-zinc battery.

The nickel-zinc battery of the present invention is a rechargeablebattery with high power and adequate energy, which is four times as thatof lead acid batteries. At the to same time, the nickel-zinc battery ofthe present invention does not make use of lead (Pb), Cadmium (Cd) andmercury (Hg) and hence has low environmental pollution while having highpower and adequate energy, has a high safety level (non-inflammable) inview of low hydrogen evolution, and maintaining a low cost formanufacture.

For example, the cathode additive according to the preferred embodimentis embodied in a nickel cathode for nickel-zinc battery for providingfeatures of long life, long-term storage and excellent performance ofhigh rate discharging to the cathode, which is simple in structure, lowcost of manufacture and with improved safety, thereby capable ofincreasing the overall efficiency and lifespan of the nickel-zincbattery.

In particular, the cell construct according to the preferred embodimentof the present invention comprises a nickel electrode 20 which acts as acathode, a zinc electrode 30 which acts as an anode, an electrolyte 40and a membrane 50 disposed between the nickel and the zinc electrodes20, 30. Preferably, the nickel electrode 20 is manufactured by combininga powdered mixture of a plurality of desired materials. In particular,the nickel electrode 20 is manufactured by combining nickel oxyhydroxide(NiOOH), nickel metal, transition metal oxide such as ruthenium oxideRu02, and/or metal oxide or hydroxide such as calcium hydroxide Ca(OH)2with a rare earth oxide such as yttrium oxide Y203, and a binder that isrolled onto a suitable current collector such as nickel foam.

In other words, the present invention provides a method of manufactureof nickel electrode 20 for a nickel-zinc battery, comprising the stepsof:

(a) providing a nickel oxyhydroxide (NiOOH) and a nickel metal;

(b.1) adding a first additive consisting of transition metal oxide tothe oxyhydroxide and the nickel metal; and

(c) adding a binder for combining the first additive to the nickeloxyhydroxide and the nickel metal.

Preferably, the transition metal oxide of the first additive isruthenium oxide (Ru02) and the binder is carboxymethyl cellulose (CMC)and/or polytetrafluoroethylene (PTFE). Preferably, after step (b.1), themethod further comprises the step of:

(b.2) adding a second additive consisting of metal oxide or hydroxidewith a rare earth oxide to the oxyhydroxide and the nickel metal suchthat an electrode capacity and a shelf life of the electrode isincreased. For example, the second additive is calcium hydroxide Ca(OH)2with yttrium oxide Y2O3.

It is worth mentioning that zinc oxide ZnO or hydroxide Zn(OH)2 can alsobe added to facilitate charger transfer and improve the high-ratedischarging characteristic of the nickel-zinc cell. The concentration ofthe zinc oxide or hydroxide is approximately 0.1% to 5%.

In other words, the metal oxide or hydroxide in step (b.2) of the methodof manufacture is zinc oxide or hydroxide in a concentration ofapproximately 0.1% to 5%.

The nickel electrode 20 according to a first exemplary embodiment, whichis adapted for acting as the cathode in the nickel-zinc battery,consists of nickel oxyhydroxide in a concentration from approximately50% to 98%, nickel metal powder in a concentration of approximately 1%to 20%, a first additive of transition metal oxide such as rutheniumoxide RuO2 and rhodium oxide (Rh02) in a concentration of approximately0.05% to 5%, and a binder such as carboxymethyl cellulose CMC andpolytetrafluoroethylene PTFE in a concentration of approximately 0.05%to 5% by its solid content. The nickel electrode 20 may further consistof a second additive which is a mixture of metal oxide or hydroxide anda rare earth oxide. In particular, the second additive contains one ormore metal oxide or hydroxide which is selected from the groupconsisting of MgO, Mg(OH)2, Zr02, Zr(OH)4, CaO, Ca(OH)2, SrO and Sr(OH)2and one or more rare earth oxide which is selected from the groupconsisting of Y203, Yb203 and Lu203. The percentage of the metal oxideor hydroxide is ranged from 0.05% to 5% and that of the rare metal oxideis ranged from 0.05% to 5%. The ratio of metal oxide or hydroxide to therare metal oxide is 1:3. The nickel electrode 20 may further consist ofa third additive which is zinc oxide or hydroxide ZnO or Zn(OH)2 in aconcentration of approximately 0.1% to 5%.

In particular, according to a first exemplary embodiment of the nickelelectrode 20 according to the preferred embodiment of the presentinvention, which is adapted for acting as the cathode in the nickel-zincbattery, the nickel electrode 20 consists of 90% nickel oxyhydroxide, 5%nickel metal powder, a first additive of transition metal oxide which is0.5% ruthenium oxide RuO2, and a binder consisting of 0.22%carboxymethyl cellulose CMC (solid content) and 0.6%polytetrafluoroethylene PTFE (solid content). Compared to conventionalcell with 94% nickel oxyhydroxide, 4% cobalt oxide (CoO), 0.6% CMC(solid content) and 1.4% PTFE (solid content), the first exemplaryembodiment of nickel electrode 20 has a greatly increased life cycle andstorage life.

In particular, according to a second exemplary embodiment of the nickelelectrode 20 according to the preferred embodiment of the presentinvention, the nickel electrode consists of 90% nickel oxyhydroxide,4.3% nickel metal powder, a first additive of transition metal oxidewhich is 0.4% ruthenium oxide RuO2, a second additive consisting of 0.2%calcium hydroxide Ca(OH)2 and 0.6% yttrium oxide Y203, and a binderconsisting of 0.24% carboxymethyl cellulose CMC (solid content) and0.58% polytetrafluoroethylene PTFE (solid content). Compared toconventional cell with 94% nickel oxyhydroxide, 4% cobalt oxide (CoO),0.6% CMC (solid content) and 1.4% PTFE (solid content), the secondexemplary embodiment of nickel electrode 20 has a greatly prolonged lifecycle and shelf life.

In particular, according to a third exemplary embodiment of the nickelelectrode 20 according to the preferred embodiment of the presentinvention, the nickel electrode 20 consists of 90% nickel oxyhydroxide,5% nickel metal powder, a first additive of transition metal oxide whichis 0.5% ruthenium oxide RuO2, a second additive consisting of 0.4% zincoxide ZnO and 0.4% yttrium oxide Y203, and a binder consisting of 0.22%carboxymethyl cellulose CMC (solid content) and 0.6%polytetrafluoroethylene PTFE (solid content). Compared to conventionalcell with 94% nickel oxyhydroxide, 4% cobalt oxide (CoO), 0.6% CMC(solid content) and 1.4% PTFE (solid content), the third exemplaryembodiment of nickel electrode 20 has a greatly prolonged life cycle andincreased high-rate discharging property.

It is worth mentioning that nickel metal powder or other conductiveagents are added to improve the conductivity of the cathode and are notreactants for carrying out reaction at the cathode. The nickel metalpowder or other conductive agents are preferably super small and evenparticles which have a high porosity, low apparent density and highspecific area, adapted for generating a good conductive network in thecell, thereby greatly increasing the charging and discharging rate ofreactants (which are active substances for reaction at the cathode) andfurther promoting the charging and discharging electrons for largecurrent flow. Accordingly, the internal resistance is reduced and thebattery life is increased.

Conventional cell makes use of cobalt compounds such as cobalt, cobaltoxides and hydroxides as an additive in the cathode which is dissolvedin alkaline electrolyte solution to increase conductivity and capacity.However, the dissolved cobalt compounds in the electrolyte react withthe zinc anode and promote hydrogen evolution at the anode which make itundesirable to use for nickel-zinc battery. The present invention is abreakthrough to solve the problem of low electrical conductivity and lowcapacity in the absence of cobalt compounds at the nickel cathode,through the addition of ruthenium oxide (Ru02) and/or rhodium oxide(Rh02) compounds as additives to improve the electrical properties ofthe nickel cathode.

Ruthenium oxide (RuO2) has great capacity to store charge when used inaqueous solutions. In particular, Ru02 by itself is a poor catalystbecause its surface area is greatly decreased without the presence of ahydrate. By foiming their hydrates, ruthenium oxide has great propertiesto improve the conductivity and capacity for the nickel cathode.

Rhodium oxide (RhO2) also has the characteristics of improving thecarrier injection from rhodium-oxide-coated indium tin oxide. When Rh02is added into the cathode paste, it also improves the electricalproperties of the cathode electrode through enhancement of carrierinjection into the metal oxides.

In addition, the second additive contains one or more metal oxide orhydroxide which is selected from the group consisting of MgO, Mg(OH)2,Zr02, Zr(OH)4, CaO, Ca(OH)2, SrO and Sr(OH)2 and one or more rare earthoxide which is selected from the group consisting of Y203, Yb203 andLu203. The percentage of the metal oxide or hydroxide is ranged from0.05% to 5% and that of the rare metal oxide is ranged from 0.05% to 5%.The ratio of metal oxide or hydroxide to the rare metal oxide is 1:3.

It is worth mentioning that a series of experiments have proved that theadditives can greatly increase the capacity of the active materials ofthe cathode. The additive also promotes the oxygen evolution,overpotential and charging efficiency of the cathode. More importantly,the additives of the present invention can effectively increase thecycling life of the cell and slow down the decrease of capacity.

In order to demonstrate the effectiveness of the cathode composition, apreferred and selected testing embodiment comprising 90% nickeloxyhydroxide, 4.3% nickel metal powder, 0.4% ruthenium oxide, 0.6% Y203,0.2% Ca(OH)2, 0.24% CMC, and 0.58% PTFE is used for testing. The resultsshow that the cell has a much longer cycle life and much less thedecrease of the capacity over conventional nickel-zinc cell in which 94%nickel oxyhydroxide, 4% cobalt oxide (CoO), 0.6% CMC, and 1.4% PTFE areused. The cycle life of the Ni—Zn battery of the present invention issignificant longer than the conventional nickel-zinc cell. In otherwords, the present invention has greatly improved the cycle life of theNi—Zn battery.

Another discovery of our research is that, in order to reach the besteffects the two substances: the metal oxide or hydroxide (at least oneof MgO, Mg(OH)2, Zr02, Zr(OH)4, CaO, Ca(OH)2 SrO, Sr(OH)2, and the rareearth oxide (at least one of Y203, Yb203, and Lu203) must be presenttogether in the cathode mixture.

Conventional Ni electrode is likely to have only a moderate chargingefficiency and cause the oxygen evolution, especially at the latecharging stage. Adding calcium compounds can increase the overpotentialto curb the evolution of oxygen. However, the calcium compounds do notenhance the conductivity of the cathode. Adding cobalt can increase theconductivity of active substances and the cobalt is also good for thereaction transformation in the cathode. Therefore, adding cobalt andcalcium can obviously increase the use ratio and charging/dischargingoverpotential of the active substances. Nevertheless, the cobaltcompounds in alkali liquid are likely to be dissolved in theelectrolyte, thus making the Zn anode evolve hydrogen easily andresulting in high internal pressure and high risk of leakage. Theaddition of cobalt fails to provide a solution to a Ni—Zn battery.

Adding rare earth compounds can increase the overpotential to curb theoxygen evolution, especially improving the high temperature performanceof active substances. The rare earth compounds Y203, Yb203, and Lu203are selected as additives and their influences on the high temperatureperformance of Ni electrode are researched. A comparison is made on theperformance of a battery with Y203 and another one without the rareearth additive. The results show that the rare earth additives can curbthe evolution of oxygen in the charging process of the Ni electrode andpromote the charging efficiency at high temperature. At the same time,it shows that the battery with Y203 additive is relatively easy to beactivated so that it can shorten the activation process and reduce themanufacturing cost of the battery. Moreover, battery with Lu203 additivehas the highest capacity under high temperature while battery with Y203additive has the highest charging efficiency of the cathode.

Battery added with calcium (Ca) compounds, such as CaF2 and Ca(OH)2, incathode has resulted in high capacity. This is due to the oxygenevolution overpotential in the late period of charging for the cathodehas been obviously enhanced, resulting in the large increase of chargingefficiency of the Ni electrode, so that increase the usage of the activematerial of NiOOH. When Ca compounds, Y203 and/or Lu203 are addedtogether, they can greatly increase the charging efficiency, curb theoxygen evolution, promote use rate of NiOOH substance, and reduce theinflation and electrode material shedding, enhancing the stability of aNi—Zn battery.

Optionally, the cathode composition of the present invention furtherincludes a zinc oxide (ZnO or Zn(OH)2) as an additive to facilitatecharger transfer and improve the high-rate discharging characteristicsof the nickel-zinc cell. A select testing embodiment with ZnO additivecomprising 90% nickel oxyhydroxide, 5% nickel metal powder, 0.5%ruthenium oxide, 0.4% Y203, 0.4% ZnO, 0.22% CMC, and 0.6% PTFE is usedfor testing. The results show that the nickel-zinc cell has a muchlonger cycle life and high rate discharging over conventional cell with94% nickel oxyhydroxide, 4% cobalt oxide (CoO), 0.6% CMC, and 1.4% PTFE.The performance of a sub-C size battery with a rated capacity of 2200mAh is shown in table 1 as follows:

TABLE 1 0.2 C 1 C 5 C 10 C 20 C dis- dis- dis- dis- dis- chargingcharging charging charging charging AC internal capacity capacitycapacity capacity capacity resistance 2200 mAh 2168 mAh 1995 mAh 1876mAh 1786 mAh 3.8 mΩ

Preferably, the cell construct for facilitating the Nickel cathode 20 ofthe Ni—Zn of the present invention comprises a plate of nickel foamadapted for being filled by active substances through a dry or wetprocess. The Nickel cathode has an uncovered part at one edge whichdefines a current collector belt, shortening distance for electronicmovement and reducing electric resistance, for providing excellentperformance and thereby meeting requirements of large currentdischarging.

Preferably, the cell construct further provide a nickel foil welded atone side of the cathode defining a conductive anti-shake joint so as toenhance an anti-shake performance of the battery.

In other words, the nickel-zinc battery of the present inventioncomprises a cell body 10 defining a cell cavity 11, a nickel cathode 20comprising a plate of nickel foam 22 filled with a plurality of activematerials, a zinc anode 30, a membrane 50, and an electrolyte 40communicated between the cathode 20 and the anode 30. The activematerials include a first additive consisting of transition metal oxide,a second additive consisting of metal oxide or hydroxide with a rareearth oxide and/or zinc oxide or hydroxide. Preferably, the nickelcathode 20 has an uncovered part at one edge which defines a currentcollector belt 23 for providing excellent performance and therebymeeting requirements of large current discharging and a nickel foil 21welded at one side of the cathode 20 defining a conductive anti-shakejoint so as to enhance an anti-shake performance of the battery.

One skilled in the art will understand that the embodiment of thepresent invention as shown in the drawings and described above isexemplary only and not intended to be limiting.

It will thus be seen that the objects of the present invention have beenfully and effectively accomplished. It embodiments have been shown anddescribed for the purposes of illustrating the functional and structuralprinciples of the present invention and is subject to change withoutdeparture from such principles. Therefore, this invention includes allmodifications encompassed within the spirit and scope of the followingclaims.

What is claimed is:
 1. A method of manufacturing a nickel electrode fora nickel-zinc battery, comprising the steps of: (a) providing a nickeloxyhydroxide (NiOOH) and a nickel metal; (b) adding a first additiveconsisting of transition metal oxide to said nickel oxyhydroxide andsaid nickel metal; and (c) adding a binder for combining said firstadditive to said nickel oxyhydroxide and said nickel metal, wherein saidfirst additive contains one or more transition metal oxides selectedfrom a group consisting of ruthenium oxide (RuO₂) and rhodium oxide(RhO₂); wherein the step (b) further comprises the step of: (b.1) addinga second additive consisting of (i) a metal oxide with one or more rareearth oxides or (ii) a metal hydroxide with one or more rare earthoxides to said nickel oxyhydroxide and said nickel metal to increase anelectrode capacity and a shelf life of said nickel electrode, whereinsaid binder combines said first additive and said second additive tosaid nickel oxyhydroxide and said nickel metal; and (b.2) adding a zincoxide (ZnO) or hydroxide (Zn(OH)₂) so as to facilitate charge transferand increase high-rate discharging ability, wherein said binder combinessaid first additive, said second additive and said zinc oxide orhydroxide to said nickel oxyhydroxide and said nickel metal.
 2. A methodof manufacturing a nickel electrode for a nickel-zinc battery,comprising the steps of: (a) providing a nickel oxyhydroxide (NiOOH) anda nickel metal; (b) adding a first additive consisting of transitionmetal oxide to said nickel oxyhydroxide and said nickel metal; and (c)adding a binder for combining said first additive to said nickeloxyhydroxide and said nickel metal, wherein said first additive containsone or more transition metal oxides selected from a group consisting ofruthenium oxide (RuO₂) and rhodium oxide (RhO₂); wherein the step (b)further comprises a step of (b.1) adding a second additive consisting of(i) a metal oxide with one or more rare earth oxides or (ii) a metalhydroxide with one or more rare earth oxides to said nickel oxyhydroxideand said nickel metal to increase an electrode capacity and a shelf lifeof said nickel electrode, wherein said binder combines said firstadditive and said second additive to said nickel oxyhydroxide and saidnickel metal; wherein said nickel oxyhydroxide has a concentration fromapproximately 50% to 98% by weight, said nickel metal in powder form hasa concentration from approximately 1% to 20% by weight, said firstadditive has a concentration from approximately 0.05% to 5% by weight,said second additive has a concentration from approximately 0.05% to 5%by weight and said binder has a concentration from approximately 0.05%to 5% by weight of solid content.
 3. The method, as recited in claim 2,wherein said metal oxide or hydroxide is selected from a groupconsisting of MgO, Mg(OH)₂, ZrO₂, Zr(OH)₄, CaO, Ca(OH)₂, SrO and Sr(OH)₂and said rare earth oxide is selected from the group consisting of Y₂O₃,Yb₂O₃ and Lu₂O₃.
 4. The method, as recited in claim 1, wherein saidnickel oxyhydroxide has a concentration from approximately 50% to 98% byweight, said nickel metal in powder form has a concentration fromapproximately 1% to 20% by weight, said first additive has aconcentration from approximately 0.05% to 5% by weight, said secondadditive has a concentration from approximately 0.05% to 5% by weight,said zinc oxide or hydroxide has a concentration from approximately 0.1%to 5% by weight and said binder has a concentration from approximately0.05% to 5% by weight of solid content.
 5. The method, as recited inclaim 4, wherein said metal oxide or hydroxide is selected from a groupconsisting of MgO, Mg(OH)₂, ZrO₂, Zr(OH)₄, CaO, Ca(OH)₂, SrO and Sr(OH)₂and said rare earth oxide is selected from the group consisting of Y₂O₃,Yb₂O₃ and Lu₂O₃.